1. Field of the Invention
The present invention relates to a vehicle seat.
2. Description of the Related Art
Heretofore, there has been known a vehicle seat which comprises a headrest, and a seat back having thereinside a back frame for supporting the headrest.
For example, Japanese Utility Model Laid-Open Publication No. 7-1842 discloses a vehicle seat which comprises an impact pressure-receiving frame and a headrest-supporting frame each provided on a back frame. The impact pressure-receiving frame has a lower end rotatably attached to a lower portion of the back frame. The headrest-supporting frame has a vertically central portion rotatably attached to an upper portion of the back frame, and a lower end connected to an upper end of the impact pressure-receiving frame.
In this vehicle seat, the headrest-supporting frame is adapted to be rotated in a direction causing an upper end thereof to be moved frontwardly in response to the impact pressure-receiving frame being inclined rearwardly. Thus, when the impact pressure-receiving frame is inclined rearwardly while being pressed by an occupant during a vehicle rear collision, the headrest supported by the upper end of the headrest-supporting frame is moved frontwardly in response to the inclination of the impact pressure-receiving frame. Thus, it becomes possible to reduce a distance between the headrest and a head of the occupant so as to protect a neck region of the occupant.
However, due to the mechanism in which two frames consisting of the impact pressure-receiving frame and the headrest-supporting frame are provided on the back frame, wherein the headrest-supporting frame and the impact pressure-receiving frame are operably coupled, the vehicle seat disclosed in the above Patent Document has a problem that a seat structure becomes complicated.